22 



Psyche 



[April 



magnified), segments as follows: III . 0924-. 1001 mm., IV (base) 

 .0463-.0539 mm., IV (unguis) .0539-.0616 mm., Ill with a distal 

 sensorium and base of IV with a distal group composed of one large 

 one and several smaller ones. III as a rule imbricated but not as 

 strongly as IV, the whole with a few short spinelike hairs; corni- 

 cles short, .0231 mm., broad, cylindrical or very nearly so, and 

 rounded at distal end; rostrum reaching to or extending some- 

 what beyond metacoxa (varying in extent, like antennje, with feed- 

 ing, as in malifolioe) ; legs armed with spinelike hairs, anterior tibise 

 .1463-1771 mm., intermediate tibia? .1617-. 2079, metatibia^ .1925- 

 .2387 mm. ; prothoracic and first and last pairs of abdominal lat- 

 eral tubercles comparatively prominent and the last abdominal 

 pair usually quite conspicuous — (all lose in conspicuousness as the 

 insect body enlarges, but under higher magnification the last ab- 

 dominal pair is quite easily made out in live specimejis which have 

 not fed too far, and is a very good distinguishing character) ; length 

 of body .5236-.8162 mm., width at widest part .2772-.4004 mm. 



3. A. prunifoliae Fitch (Apple-Grain Aphis). 



Dull light green or dull dark green, anterior and dorsal aspects of 

 head dusky to blackish and very often with a pale or uncolored 

 median longitudinal line; antennae, base of rostrum, caudal end of 

 abdomen ventrally, and legs dusky — distal portions of femora, 

 tibia?, and of tarsi may be still darker; cornicles and about ^ distal 

 portion of rostrum black or blackish; eyes black 

 (in mounted specimens deep red). Newly- 

 hatched specimens are light green, with head 

 and thorax (at least first two segments) still 

 lighter or pale yellow-green; appendages with 

 a cast of the color of the body, although practi- 

 cally colorless in part sometimes; femora us- 

 ually yellow-green. 



Antennae stoutish, reaching to about end of 

 thorax and "shortening up" somewhat with 

 feeding, flagellum or unguis about twice as long 

 as base, segments as follows: III .0924-. 1001 

 mm., IV (base) .0385-.0462 mm., IV (unguis) 

 .0847-. 1001 mm., Ill with a distal sensorium 

 and base of IV with a distal group composed 



B 



A "^ 



Fig. 3. — Antenna 

 and cornicle oi Aphis 

 pruni folios Fitch, 

 about X150. 



